The invention relates generally to multi-chip module circuits, and more particularly to a multi-chip module that is testable and reconfigurable based on testing results.
Multi-chip modules are known to include the package that houses an interconnecting substrate upon which a plurality of die are coupled. The number of die that may be included in the multi-chip module can vary greatly. In order to ensure functionality of a multi-chip module, extensive tests are performed upon each of the die within the multi-chip module. Although it is well understood how to perform these tests before the die are mounted within the multi-chip module, testing issues can arise once the entire module has been packaged. Signals that are routed directly between two different integrated circuits within the module may not be accessible external to the multi-chip module.
As the complexity of multi-chip modules in terms of the number of integrated circuits and interconnect within the multi-chip module continues to increase, the possibility of failure on the part of one or more of the integrated circuits deposited on the die within the multi-chip module also increases. In addition to this, the robustness of the overall multi-chip module is related to the complexity of the integrated circuits that are deposited upon each of the die within the multi-chip module, as more complex circuits are more likely to include a defect leading to failure.
Understandably, problems arise when failures are detected within the multi-chip module. In such instances the entire multi-chip module is normally rendered unusable, and is therefore scrapped. Because the circuits within the multi-chip module are designed and configured with the assumption that all of the circuitry within the multi-chip module will be functional, non-functionality of any one portion will render the entire system inoperable. Failures within a multi-chip module can be prohibitively expensive as the number of die within the multi-chip module and the complexity of those die increases.
For example, if a manufacturer wished to integrate a number of complex and expensive circuits upon a multi-chip module, the manufacturer may be hesitant to do so for fear that the process of integration would inflict defects upon one or more of the integrated circuits. In such a case, the cost of all of the integrated circuits combined on the multi-chip module would be incurred due to the failure of any one. Similarly, problems with the mounting substrate can cause the entire multi-chip module to fail. Thus, the cost of producing complex multi-chip modules can be prohibitive.
Therefore a need exists for a method and apparatus that allows for complete testing of a multi-chip module, and also allows for reconfiguration of a multi-chip module based on the testing results.